libavcodec/shorten.c

   1 /*
   2  * Shorten decoder
   3  * Copyright (c) 2005 Jeff Muizelaar
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * Shorten decoder
  25  * @author Jeff Muizelaar
  26  *
  27  */
  28
  29 #include <limits.h>
  30 #include "avcodec.h"
  31 #include "bytestream.h"
  32 #include "get_bits.h"
  33 #include "golomb.h"
  34 #include "internal.h"
  35
  36 #define MAX_CHANNELS 8
  37 #define MAX_BLOCKSIZE 65535
  38
  39 #define OUT_BUFFER_SIZE 16384
  40
  41 #define ULONGSIZE 2
  42
  43 #define WAVE_FORMAT_PCM 0x0001
  44
  45 #define DEFAULT_BLOCK_SIZE 256
  46
  47 #define TYPESIZE 4
  48 #define CHANSIZE 0
  49 #define LPCQSIZE 2
  50 #define ENERGYSIZE 3
  51 #define BITSHIFTSIZE 2
  52
  53 #define TYPE_S16HL 3
  54 #define TYPE_S16LH 5
  55
  56 #define NWRAP 3
  57 #define NSKIPSIZE 1
  58
  59 #define LPCQUANT 5
  60 #define V2LPCQOFFSET (1 << LPCQUANT)
  61
  62 #define FNSIZE 2
  63 #define FN_DIFF0        0
  64 #define FN_DIFF1        1
  65 #define FN_DIFF2        2
  66 #define FN_DIFF3        3
  67 #define FN_QUIT         4
  68 #define FN_BLOCKSIZE    5
  69 #define FN_BITSHIFT     6
  70 #define FN_QLPC         7
  71 #define FN_ZERO         8
  72 #define FN_VERBATIM     9
  73
  74 /** indicates if the FN_* command is audio or non-audio */
  75 static const uint8_t is_audio_command[10] = { 1, 1, 1, 1, 0, 0, 0, 1, 1, 0 };
  76
  77 #define VERBATIM_CKSIZE_SIZE 5
  78 #define VERBATIM_BYTE_SIZE 8
  79 #define CANONICAL_HEADER_SIZE 44
  80
  81 typedef struct ShortenContext {
  82     AVCodecContext *avctx;
  83     GetBitContext gb;
  84
  85     int min_framesize, max_framesize;
  86     unsigned channels;
  87
  88     int32_t *decoded[MAX_CHANNELS];
  89     int32_t *decoded_base[MAX_CHANNELS];
  90     int32_t *offset[MAX_CHANNELS];
  91     int *coeffs;
  92     uint8_t *bitstream;
  93     int bitstream_size;
  94     int bitstream_index;
  95     unsigned int allocated_bitstream_size;
  96     int header_size;
  97     uint8_t header[OUT_BUFFER_SIZE];
  98     int version;
  99     int cur_chan;
 100     int bitshift;
 101     int nmean;
 102     int internal_ftype;
 103     int nwrap;
 104     int blocksize;
 105     int bitindex;
 106     int32_t lpcqoffset;
 107     int got_header;
 108     int got_quit_command;
 109 } ShortenContext;
 110
 111 static av_cold int shorten_decode_init(AVCodecContext *avctx)
 112 {
 113     ShortenContext *s = avctx->priv_data;
 114     s->avctx          = avctx;
 115     avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
 116
 117     return 0;
 118 }
 119
 120 static int allocate_buffers(ShortenContext *s)
 121 {
 122     int i, chan;
 123     int *coeffs;
 124     void *tmp_ptr;
 125
 126     for (chan = 0; chan < s->channels; chan++) {
 127         if (FFMAX(1, s->nmean) >= UINT_MAX / sizeof(int32_t)) {
 128             av_log(s->avctx, AV_LOG_ERROR, "nmean too large\n");
 129             return AVERROR_INVALIDDATA;
 130         }
 131         if (s->blocksize + s->nwrap >= UINT_MAX / sizeof(int32_t) ||
 132             s->blocksize + s->nwrap <= (unsigned)s->nwrap) {
 133             av_log(s->avctx, AV_LOG_ERROR,
 134                    "s->blocksize + s->nwrap too large\n");
 135             return AVERROR_INVALIDDATA;
 136         }
 137
 138         tmp_ptr =
 139             av_realloc(s->offset[chan], sizeof(int32_t) * FFMAX(1, s->nmean));
 140         if (!tmp_ptr)
 141             return AVERROR(ENOMEM);
 142         s->offset[chan] = tmp_ptr;
 143
 144         tmp_ptr = av_realloc(s->decoded_base[chan], (s->blocksize + s->nwrap) *
 145                              sizeof(s->decoded_base[0][0]));
 146         if (!tmp_ptr)
 147             return AVERROR(ENOMEM);
 148         s->decoded_base[chan] = tmp_ptr;
 149         for (i = 0; i < s->nwrap; i++)
 150             s->decoded_base[chan][i] = 0;
 151         s->decoded[chan] = s->decoded_base[chan] + s->nwrap;
 152     }
 153
 154     coeffs = av_realloc(s->coeffs, s->nwrap * sizeof(*s->coeffs));
 155     if (!coeffs)
 156         return AVERROR(ENOMEM);
 157     s->coeffs = coeffs;
 158
 159     return 0;
 160 }
 161
 162 static inline unsigned int get_uint(ShortenContext *s, int k)
 163 {
 164     if (s->version != 0)
 165         k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
 166     return get_ur_golomb_shorten(&s->gb, k);
 167 }
 168
 169 static void fix_bitshift(ShortenContext *s, int32_t *buffer)
 170 {
 171     int i;
 172
 173     if (s->bitshift != 0)
 174         for (i = 0; i < s->blocksize; i++)
 175             buffer[i] <<= s->bitshift;
 176 }
 177
 178 static int init_offset(ShortenContext *s)
 179 {
 180     int32_t mean = 0;
 181     int chan, i;
 182     int nblock = FFMAX(1, s->nmean);
 183     /* initialise offset */
 184     switch (s->internal_ftype) {
 185     case TYPE_S16HL:
 186     case TYPE_S16LH:
 187         mean = 0;
 188         break;
 189     default:
 190         av_log(s->avctx, AV_LOG_ERROR, "unknown audio type");
 191         return AVERROR_INVALIDDATA;
 192     }
 193
 194     for (chan = 0; chan < s->channels; chan++)
 195         for (i = 0; i < nblock; i++)
 196             s->offset[chan][i] = mean;
 197     return 0;
 198 }
 199
 200 static int decode_wave_header(AVCodecContext *avctx, const uint8_t *header,
 201                               int header_size)
 202 {
 203     int len;
 204     short wave_format;
 205
 206     if (bytestream_get_le32(&header) != MKTAG('R', 'I', 'F', 'F')) {
 207         av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
 208         return AVERROR_INVALIDDATA;
 209     }
 210
 211     header += 4; /* chunk size */
 212
 213     if (bytestream_get_le32(&header) != MKTAG('W', 'A', 'V', 'E')) {
 214         av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
 215         return AVERROR_INVALIDDATA;
 216     }
 217
 218     while (bytestream_get_le32(&header) != MKTAG('f', 'm', 't', ' ')) {
 219         len     = bytestream_get_le32(&header);
 220         header += len;
 221     }
 222     len = bytestream_get_le32(&header);
 223
 224     if (len < 16) {
 225         av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
 226         return AVERROR_INVALIDDATA;
 227     }
 228
 229     wave_format = bytestream_get_le16(&header);
 230
 231     switch (wave_format) {
 232     case WAVE_FORMAT_PCM:
 233         break;
 234     default:
 235         av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
 236         return AVERROR(ENOSYS);
 237     }
 238
 239     header += 2;        // skip channels    (already got from shorten header)
 240     avctx->sample_rate = bytestream_get_le32(&header);
 241     header += 4;        // skip bit rate    (represents original uncompressed bit rate)
 242     header += 2;        // skip block align (not needed)
 243     avctx->bits_per_coded_sample = bytestream_get_le16(&header);
 244
 245     if (avctx->bits_per_coded_sample != 16) {
 246         av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n");
 247         return AVERROR(ENOSYS);
 248     }
 249
 250     len -= 16;
 251     if (len > 0)
 252         av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
 253
 254     return 0;
 255 }
 256
 257 static void output_buffer(int16_t **samples, int nchan, int blocksize,
 258                           int32_t **buffer)
 259 {
 260     int i, ch;
 261     for (ch = 0; ch < nchan; ch++) {
 262         int32_t *in  = buffer[ch];
 263         int16_t *out = samples[ch];
 264         for (i = 0; i < blocksize; i++)
 265             out[i] = av_clip_int16(in[i]);
 266     }
 267 }
 268
 269 static const int fixed_coeffs[3][3] = {
 270     { 1,  0,  0 },
 271     { 2, -1,  0 },
 272     { 3, -3,  1 }
 273 };
 274
 275 static int decode_subframe_lpc(ShortenContext *s, int command, int channel,
 276                                int residual_size, int32_t coffset)
 277 {
 278     int pred_order, sum, qshift, init_sum, i, j;
 279     const int *coeffs;
 280
 281     if (command == FN_QLPC) {
 282         /* read/validate prediction order */
 283         pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
 284         if (pred_order > s->nwrap) {
 285             av_log(s->avctx, AV_LOG_ERROR, "invalid pred_order %d\n",
 286                    pred_order);
 287             return AVERROR(EINVAL);
 288         }
 289         /* read LPC coefficients */
 290         for (i = 0; i < pred_order; i++)
 291             s->coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
 292         coeffs = s->coeffs;
 293
 294         qshift = LPCQUANT;
 295     } else {
 296         /* fixed LPC coeffs */
 297         pred_order = command;
 298         coeffs     = fixed_coeffs[pred_order - 1];
 299         qshift     = 0;
 300     }
 301
 302     /* subtract offset from previous samples to use in prediction */
 303     if (command == FN_QLPC && coffset)
 304         for (i = -pred_order; i < 0; i++)
 305             s->decoded[channel][i] -= coffset;
 306
 307     /* decode residual and do LPC prediction */
 308     init_sum = pred_order ? (command == FN_QLPC ? s->lpcqoffset : 0) : coffset;
 309     for (i = 0; i < s->blocksize; i++) {
 310         sum = init_sum;
 311         for (j = 0; j < pred_order; j++)
 312             sum += coeffs[j] * s->decoded[channel][i - j - 1];
 313         s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) +
 314                                  (sum >> qshift);
 315     }
 316
 317     /* add offset to current samples */
 318     if (command == FN_QLPC && coffset)
 319         for (i = 0; i < s->blocksize; i++)
 320             s->decoded[channel][i] += coffset;
 321
 322     return 0;
 323 }
 324
 325 static int read_header(ShortenContext *s)
 326 {
 327     int i, ret;
 328     int maxnlpc = 0;
 329     /* shorten signature */
 330     if (get_bits_long(&s->gb, 32) != AV_RB32("ajkg")) {
 331         av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
 332         return AVERROR_INVALIDDATA;
 333     }
 334
 335     s->lpcqoffset     = 0;
 336     s->blocksize      = DEFAULT_BLOCK_SIZE;
 337     s->nmean          = -1;
 338     s->version        = get_bits(&s->gb, 8);
 339     s->internal_ftype = get_uint(s, TYPESIZE);
 340
 341     s->channels = get_uint(s, CHANSIZE);
 342     if (!s->channels) {
 343         av_log(s->avctx, AV_LOG_ERROR, "No channels reported\n");
 344         return AVERROR_INVALIDDATA;
 345     }
 346     if (s->channels > MAX_CHANNELS) {
 347         av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
 348         s->channels = 0;
 349         return AVERROR_INVALIDDATA;
 350     }
 351     s->avctx->channels = s->channels;
 352
 353     /* get blocksize if version > 0 */
 354     if (s->version > 0) {
 355         int skip_bytes;
 356         unsigned blocksize;
 357
 358         blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
 359         if (!blocksize || blocksize > MAX_BLOCKSIZE) {
 360             av_log(s->avctx, AV_LOG_ERROR,
 361                    "invalid or unsupported block size: %d\n",
 362                    blocksize);
 363             return AVERROR(EINVAL);
 364         }
 365         s->blocksize = blocksize;
 366
 367         maxnlpc  = get_uint(s, LPCQSIZE);
 368         s->nmean = get_uint(s, 0);
 369
 370         skip_bytes = get_uint(s, NSKIPSIZE);
 371         for (i = 0; i < skip_bytes; i++)
 372             skip_bits(&s->gb, 8);
 373     }
 374     s->nwrap = FFMAX(NWRAP, maxnlpc);
 375
 376     if ((ret = allocate_buffers(s)) < 0)
 377         return ret;
 378
 379     if ((ret = init_offset(s)) < 0)
 380         return ret;
 381
 382     if (s->version > 1)
 383         s->lpcqoffset = V2LPCQOFFSET;
 384
 385     if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
 386         av_log(s->avctx, AV_LOG_ERROR,
 387                "missing verbatim section at beginning of stream\n");
 388         return AVERROR_INVALIDDATA;
 389     }
 390
 391     s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
 392     if (s->header_size >= OUT_BUFFER_SIZE ||
 393         s->header_size < CANONICAL_HEADER_SIZE) {
 394         av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n",
 395                s->header_size);
 396         return AVERROR_INVALIDDATA;
 397     }
 398
 399     for (i = 0; i < s->header_size; i++)
 400         s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
 401
 402     if ((ret = decode_wave_header(s->avctx, s->header, s->header_size)) < 0)
 403         return ret;
 404
 405     s->cur_chan = 0;
 406     s->bitshift = 0;
 407
 408     s->got_header = 1;
 409
 410     return 0;
 411 }
 412
 413 static int shorten_decode_frame(AVCodecContext *avctx, void *data,
 414                                 int *got_frame_ptr, AVPacket *avpkt)
 415 {
 416     AVFrame *frame     = data;
 417     const uint8_t *buf = avpkt->data;
 418     int buf_size       = avpkt->size;
 419     ShortenContext *s  = avctx->priv_data;
 420     int i, input_buf_size = 0;
 421     int ret;
 422
 423     /* allocate internal bitstream buffer */
 424     if (s->max_framesize == 0) {
 425         void *tmp_ptr;
 426         s->max_framesize = 1024; // should hopefully be enough for the first header
 427         tmp_ptr = av_fast_realloc(s->bitstream, &s->allocated_bitstream_size,
 428                                   s->max_framesize);
 429         if (!tmp_ptr) {
 430             av_log(avctx, AV_LOG_ERROR, "error allocating bitstream buffer\n");
 431             return AVERROR(ENOMEM);
 432         }
 433         s->bitstream = tmp_ptr;
 434     }
 435
 436     /* append current packet data to bitstream buffer */
 437     if (1 && s->max_framesize) { //FIXME truncated
 438         buf_size       = FFMIN(buf_size, s->max_framesize - s->bitstream_size);
 439         input_buf_size = buf_size;
 440
 441         if (s->bitstream_index + s->bitstream_size + buf_size >
 442             s->allocated_bitstream_size) {
 443             memmove(s->bitstream, &s->bitstream[s->bitstream_index],
 444                     s->bitstream_size);
 445             s->bitstream_index = 0;
 446         }
 447         if (buf)
 448             memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf,
 449                    buf_size);
 450         buf               = &s->bitstream[s->bitstream_index];
 451         buf_size         += s->bitstream_size;
 452         s->bitstream_size = buf_size;
 453
 454         /* do not decode until buffer has at least max_framesize bytes or
 455          * the end of the file has been reached */
 456         if (buf_size < s->max_framesize && avpkt->data) {
 457             *got_frame_ptr = 0;
 458             return input_buf_size;
 459         }
 460     }
 461     /* init and position bitstream reader */
 462     init_get_bits(&s->gb, buf, buf_size * 8);
 463     skip_bits(&s->gb, s->bitindex);
 464
 465     /* process header or next subblock */
 466     if (!s->got_header) {
 467         if ((ret = read_header(s)) < 0)
 468             return ret;
 469         *got_frame_ptr = 0;
 470         goto finish_frame;
 471     }
 472
 473     /* if quit command was read previously, don't decode anything */
 474     if (s->got_quit_command) {
 475         *got_frame_ptr = 0;
 476         return avpkt->size;
 477     }
 478
 479     s->cur_chan = 0;
 480     while (s->cur_chan < s->channels) {
 481         unsigned cmd;
 482         int len;
 483
 484         if (get_bits_left(&s->gb) < 3 + FNSIZE) {
 485             *got_frame_ptr = 0;
 486             break;
 487         }
 488
 489         cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
 490
 491         if (cmd > FN_VERBATIM) {
 492             av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
 493             *got_frame_ptr = 0;
 494             break;
 495         }
 496
 497         if (!is_audio_command[cmd]) {
 498             /* process non-audio command */
 499             switch (cmd) {
 500             case FN_VERBATIM:
 501                 len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
 502                 while (len--)
 503                     get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
 504                 break;
 505             case FN_BITSHIFT:
 506                 s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
 507                 break;
 508             case FN_BLOCKSIZE: {
 509                 unsigned blocksize = get_uint(s, av_log2(s->blocksize));
 510                 if (blocksize > s->blocksize) {
 511                     av_log(avctx, AV_LOG_ERROR,
 512                            "Increasing block size is not supported\n");
 513                     return AVERROR_PATCHWELCOME;
 514                 }
 515                 if (!blocksize || blocksize > MAX_BLOCKSIZE) {
 516                     av_log(avctx, AV_LOG_ERROR, "invalid or unsupported "
 517                                                 "block size: %d\n", blocksize);
 518                     return AVERROR(EINVAL);
 519                 }
 520                 s->blocksize = blocksize;
 521                 break;
 522             }
 523             case FN_QUIT:
 524                 s->got_quit_command = 1;
 525                 break;
 526             }
 527             if (cmd == FN_BLOCKSIZE || cmd == FN_QUIT) {
 528                 *got_frame_ptr = 0;
 529                 break;
 530             }
 531         } else {
 532             /* process audio command */
 533             int residual_size = 0;
 534             int channel = s->cur_chan;
 535             int32_t coffset;
 536
 537             /* get Rice code for residual decoding */
 538             if (cmd != FN_ZERO) {
 539                 residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
 540                 /* This is a hack as version 0 differed in the definition
 541                  * of get_sr_golomb_shorten(). */
 542                 if (s->version == 0)
 543                     residual_size--;
 544             }
 545
 546             /* calculate sample offset using means from previous blocks */
 547             if (s->nmean == 0)
 548                 coffset = s->offset[channel][0];
 549             else {
 550                 int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
 551                 for (i = 0; i < s->nmean; i++)
 552                     sum += s->offset[channel][i];
 553                 coffset = sum / s->nmean;
 554                 if (s->version >= 2)
 555                     coffset >>= FFMIN(1, s->bitshift);
 556             }
 557
 558             /* decode samples for this channel */
 559             if (cmd == FN_ZERO) {
 560                 for (i = 0; i < s->blocksize; i++)
 561                     s->decoded[channel][i] = 0;
 562             } else {
 563                 if ((ret = decode_subframe_lpc(s, cmd, channel,
 564                                                residual_size, coffset)) < 0)
 565                     return ret;
 566             }
 567
 568             /* update means with info from the current block */
 569             if (s->nmean > 0) {
 570                 int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
 571                 for (i = 0; i < s->blocksize; i++)
 572                     sum += s->decoded[channel][i];
 573
 574                 for (i = 1; i < s->nmean; i++)
 575                     s->offset[channel][i - 1] = s->offset[channel][i];
 576
 577                 if (s->version < 2)
 578                     s->offset[channel][s->nmean - 1] = sum / s->blocksize;
 579                 else
 580                     s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
 581             }
 582
 583             /* copy wrap samples for use with next block */
 584             for (i = -s->nwrap; i < 0; i++)
 585                 s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
 586
 587             /* shift samples to add in unused zero bits which were removed
 588              * during encoding */
 589             fix_bitshift(s, s->decoded[channel]);
 590
 591             /* if this is the last channel in the block, output the samples */
 592             s->cur_chan++;
 593             if (s->cur_chan == s->channels) {
 594                 /* get output buffer */
 595                 frame->nb_samples = s->blocksize;
 596                 if ((ret = ff_get_buffer(avctx, frame)) < 0) {
 597                     av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 598                     return ret;
 599                 }
 600                 /* interleave output */
 601                 output_buffer((int16_t **)frame->extended_data, s->channels,
 602                               s->blocksize, s->decoded);
 603
 604                 *got_frame_ptr = 1;
 605             }
 606         }
 607     }
 608     if (s->cur_chan < s->channels)
 609         *got_frame_ptr = 0;
 610
 611 finish_frame:
 612     s->bitindex = get_bits_count(&s->gb) - 8 * (get_bits_count(&s->gb) / 8);
 613     i           = get_bits_count(&s->gb) / 8;
 614     if (i > buf_size) {
 615         av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
 616         s->bitstream_size  = 0;
 617         s->bitstream_index = 0;
 618         return AVERROR_INVALIDDATA;
 619     }
 620     if (s->bitstream_size) {
 621         s->bitstream_index += i;
 622         s->bitstream_size  -= i;
 623         return input_buf_size;
 624     } else
 625         return i;
 626 }
 627
 628 static av_cold int shorten_decode_close(AVCodecContext *avctx)
 629 {
 630     ShortenContext *s = avctx->priv_data;
 631     int i;
 632
 633     for (i = 0; i < s->channels; i++) {
 634         s->decoded[i] = NULL;
 635         av_freep(&s->decoded_base[i]);
 636         av_freep(&s->offset[i]);
 637     }
 638     av_freep(&s->bitstream);
 639     av_freep(&s->coeffs);
 640
 641     return 0;
 642 }
 643
 644 AVCodec ff_shorten_decoder = {
 645     .name           = "shorten",
 646     .type           = AVMEDIA_TYPE_AUDIO,
 647     .id             = AV_CODEC_ID_SHORTEN,
 648     .priv_data_size = sizeof(ShortenContext),
 649     .init           = shorten_decode_init,
 650     .close          = shorten_decode_close,
 651     .decode         = shorten_decode_frame,
 652     .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
 653     .long_name      = NULL_IF_CONFIG_SMALL("Shorten"),
 654     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
 655                                                       AV_SAMPLE_FMT_NONE },
 656 };